The present invention relates generally to the field of weight-lifting exercise equipment where the weight is accelerated by the athlete during an entire lifting motion.
There are many types of weight-lifting exercise machines, and these devices vary in complexity. One of the simplest forms of such devices is a free weight, where the device is a mass with some means of gripping, and the user lifts the weight by the grips. More complex lifting equipment includes levers, pulleys, selectable weights, and/or spotting systems. In all of these cases, the stroke of the exercise occurs where the user moves a mass against gravity, using personal muscular effort.
There are many training regimens that prescribe frequency of lift, weight progression, technique of lifting etc. These regimens typically require that a mass start at a point, and that it return to the same point through one cycle of the exercise technique. This cycle defines the range of motion through which the mass should travel. The purpose of the exercise is to build strength and endurance.
The exercise devices of the prior art facilitate the user's effort while moving the mass against gravity, but they also require the user to expend effort to bring the mass back to its starting point. In addition, recording the workout has traditionally been done by hand, by writing down the pertinent data, such as mass lifted and the number of repetitions.
An exercise machine, built by the present inventor in 1996, included a mass which was accelerated upwardly against gravity by the user. A flywheel system returned the mass to its starting point. A cable system transferred the potential energy of the mass into the flywheel, and the flywheel was connected to a fan which dissipated the energy by air resistance. This system worked, but had the major disadvantage that the mass would continue to accelerate downwardly, albeit at a slower rate, requiring the user to prevent the mass from slamming into the stationary portion of the machine. Also, the device included no automatic means for monitoring the progress of the exercise.
U.S. Pat. No. 7,104,936 (Karlstrom) discloses an exercise machine which allows the user to lift a mass upward, and wherein a cylinder returns the mass to its starting point by throttling hydraulic fluid through a metering orifice. This system is useful in the applications illustrated in the patent, but lacks the ability to be used with horizontal motions, complex multi-muscle group motions such as the rowing stroke, and various mechanized lifting motions such as leg extensions.
The present invention comprises a substantial improvement over the prior art, insofar as it includes a weight-lifting machine in which a mass is automatically returned to its resting position, without the aid of the athlete. The device of the present invention also includes features which facilitate the monitoring of progress of the athlete, and the recording of relevant data. The device also provides immediate feedback to the athlete, and can signal the athlete when the exercise is not being performed correctly.